The present invention relates to a vertical type wind-driven prime mover utilizing natural wind forces and more particularly to a vertical type wind-driven prime mover which is designed so that even if the wind speed increases beyond a given value, the rotative speed of the main shaft can not increase with the increasing wind speed beyond to a given value.
It is necessary to limit the rotative speed of the main shaft of such prime mover because if the wind speed increases to excess as in a typhoon, it causes the main shaft to rotate at an extraordinarily high speed causing damage to e.g., the speed change device, connected to the prime mover or other problems such as undesirable pulsation of output energy due to irregular rotation. Heretofore, special devices, such as brakes and governors, have been attached to the main shaft or to the speed change device of wind driven prime movers to limit the rotative speed, but such brakes are large and expensive and increase the overall cost and, moreover, they cause problems.
An object of the present invention is to provide a vertical type wind-driven prime mover which is capable of positively limiting the rotative speed of the main shaft without using large and complicated devices.
Another object of the invention is to provide a vertical type wind-driven prime mover which can be installed at a relatively low position and which can be maintained or controlled with ease.